Process for the preparation of a graft copolymer including a monomer of esters of unsaturated carboxylic acids or vinyl esters and polyamide oligomers

ABSTRACT

Disclosed herein are a novel graft copolymer comprising a stock copolymer (A) of at least one monomer selected from esters of unsaturated carboxylic acids and vinyl esters (a), ethylene (b) and carbon monoxide (c), and a polyamide oligomer having a primary amino group at one end of its molecule (B) grafted on said stock copolymer, and a process for the preparation thereof. The proposed graft copolymer, when used as an adhesive, in particular for adhesion of polyvinyl chloride, exhibits excellent heat resistance and adhesion properties.

This is a continuation of copending application Ser. No. 07/718,235filed on Jun. 20, 1991, now abandoned, which is a divisional ofcopending application Ser. No. 07/403,659 filed on Aug. 6, 1989, nowU.S. Pat. No. 5,049,626.

FIELD OF THE INVENTION

The invention relates to a novel graft copolymer comprising a stockcopolymer of ethylene, a vinyl monomer and carbon monoxide which isexcellent in heat resistance and adhdesion properties. It also relatesto a process for the preparation of such a graft copolymer and to use ofthe graft copolymer.

BACKGROUND OF THE INVENTION

Non-rigid vinyl chloride resins have advantageous properties includingflexibility, transparency and toughness, and some of the properties suchas flexibility can be controlled at will by varying the amount of aplasticizer added. For these reasons, they are widely used in variousapplications including films, sheets, and extrusion molded articles.However, adhesion of non-rigid vinyl chloride resins is not necessarilyeasy. While many proposals have been made on adhesives for non-rigidvinyl chloride resins, none of them has been found completelysatisfactory. Many of the prior art adhesives for non-rigid vinylchloride resins comprises a solution of an adhesive ingredient such aschloroprene rubbers, nitrile rubbers and polyesters. Because of the useof a solvent, solution type adhesives have posed problems of pollutionof working environment, need of a step of drying the solvent andexpensive costs involved.

There have been already known solvent free adhesives which can realizethermal adhesion without suffering from the above-mentioned problems andwhich can be used in adhesion of non-rigid vinyl chloride resins. Suchknown adhesives include, for example, those based on copolymers ofethylene and vinyl acetate having vinyl chloride grafed (Japanese PatentLaid-open Publication No, 57-167,362), carboxylated copolymers ofethylene and vinyl acetate (Japanese Patent Laid-open Publication No,59-52,174) and copolymers of ethylene, vinyl acetate and carbon monoxide(Japanese Patent Laid-open Publication No, 57-165,427). However, thesecopolymers have relatively low melting points, and therefore, when anadherend coated with an adhesive comprising the copolymer mentionedabove is exposed to a hot atmosphere, adhesive failure frequently takesplace even with a slight shearing.

In view of the state of the art, as discussed above, we have studied toseek for an adhesive which is excellent in heat resistance and capableof realizing thermal adhesion. As a result we have found that a novelgraft copolymer comprising a stock copolymer (A) of at least one monomerselected from esters of unsaturated carboxylic acids and vinyl esters(a), ethylene (b) and carbon monoxide (c), and a polyamide oligomerhaving a primary amino group at one end of its molecule (B) grafted onsaid stock copolymer, is excellent in heat resistance, can realizethermal adhesion and, moreover, has other desirable properties. Theinvention is based on these findings.

OBJECT OF THE INVENTION

An object of the invention is to provide a novel graft copolymer whichis excellent in heat resistance and has desirable properties includingbeing capable of realizing thermal adhesion.

Another object of the invention is to provide a novel graft copolymerwhich can realize thermal adhesion at relatively low temperatures onnon-rigid vinyl chloride resins and other substrates, while exhibitingexcellent adhesion properties, particularly excellent heat resistantadhesion property.

Still another object of the invention is to provide a novel graftcopolymer which bas improved heat distortion resistance and heatresistant adhesion properties, compared with those of the starting stockcopolymer (A), and which, novel graft copolymer when laminated with anon-rigid vinyl chloride resin, exhibits a reduced tendency of beingswelled with a plasticizer contained in the resin.

A further object of the invention is to provide a process for thepreparation of the novel graft copolymer according to the invention.

These and other objects of the invention will become apparent from thedescription noted below.

SUMMARY OF THE INVENTION

The novel graft copolymer according to the invention comprises a stockcopolymer (A) of at least one monomer selected from esters ofunsaturated carboxylic acids and vinyl esters (a), ethylene (b) andcarbon monoxide (c), and a polyamide oligomer having a primary aminogroup at one end of its molecule (B) grafted on said stock copolymer.

The novel graft copolymer according to the invention can be prepared bygraft polymerizing the polyamide oligomer (B) above onto the stockcopolymer (A) above. The graft polymerization is preferably carried outin the presence of a carboxyl group containing compound having a numberaverage molecular weight of from 200 to 10,000 and an acid value of from15 to 300.

The novel graft copolymer according to the invention, when used as anadhesive, in particular for polyvinyl chloride, exhibits desirableadhesion properties.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a ¹³ C-NMR absorption spectrum of a graft copolymer ofExample 4;

FIG. 2 shows an IR absorption spectrum of a graft copolymer of Example9;

FIG. 3 shows an IR absorption spectrum of a graft copolymer of Example10;

FIG. 4 shows melt behavior (temperature-melt viscosity curves atindicated shear rates) of a graft copolymer of Example 9;

FIG. 5 shows an IR absorption spectrum of a graft copolymer of Example21 prepared by in the presence of a carboxyl group (hydrogenated rosin);

FIG. 6 shows an IR absorption spectrum of the same graft copolymer ofExample 21 after extraction of the hydrogenated rosin; and

FIG. 7 shows an IR absorption spectrum of the hydrogenated rosin used inExample 21.

DETAILED DESCRIPTION OF THE INVENTION

The novel graft copolymer according to the invention, the process forthe preparation thereof and use thereof will now be described in detail.

The novel graft copolymer according to the invention comprises a stockcopolymer (A) obtained by copolymering at least one monomer selectedfrom esters of unsaturated carboxylic acids and vinyl esters (a),ethylene (b) and carbon monoxide (c), and a polyamide oligomer having aprimary amino group at one end of its molecule (B) grafted on said stockcopolymer.

The monomer (a) is selected from the group consisting of esters ofunsaturated carboxylic acids and vinyl esters. As the esters ofunsaturated carboxylic acids, preferred are those derived from anα,β-unsaturated carboxylic acid such as acrylic acid, methacrylic acidand maleic acid and a straight or branched alcohol having from 1 to 10carbon atoms such as methanol, ethanol, isopropanol, n-propanol,isobutanol, n-butanol, sec.-butanol, n-hexanol, n-octanol,2-ethylhexanol and n-decanol.

Examples of the esters of unsaturated carboxylic acids include, forexample, methyl (meth)acrylate, ethyl (meth)acrylate, isobutyl(meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate,phenyl (meth)acrylate and dimethyl maleate.

Examples of the vinyl esters which can be used herein as the monomer (a)include, for example, vinyl formate, vinyl acetate and vinyl propronate.

A preferred stock copolymer (A) is composed of from 10 to 50%,preferably from 20 to 40%, by weight of said monomer (a), from 20 to89%, preferably from 40 to 78%, by weight of ethylene (b) and from 1 to30%, preferably from 2 to 20%, by weight of carbon monoxide (c). If thecarbon monoxide content of the stock copolymer is less than 1% byweight, it is not easy to graft an increased amount of the polyamideoligomer to such a stock copolymer, making it difficult to prepare agraft copolymer of good quality. Whereas unduly high carbon monoxidecontent in excess of 30% by weight adversely affects weather resistanceof the graft copolymer, and thus, limits the application fields of theproduct. When the graft copolymer according to the invention is intendedto be used as an adhesive, the stock copolymer preferably contains from5 to 20% by weight of oxygen.

While the optimum molecular weight of the stock copolymer (A) dependsupon the intended use of the graft copolymer, the stock copolymerpreferably has a weight average molecular weight of from 10⁴ to 10⁶, inparticular from 10⁴ to 5×10⁵, as measured by gel permeationchromatography (GPC). In the gel permeation chromatography used hereinthe measurment was carried out at 135° C. using o-dichlorobenzene as asolvent, and the measured value was calculated in terms of the molecularweight of polystyrene used as a standard.

The stock copolymer (A) which can be used herein is well known in theart, and can be generally prepared by radical copolymerization of themonomer (a), ethylene (b) and carbon monoxide (c) at a temperature of150°-250° C. and under a pressure of 500-3000 kg/cm² in bulk. It canalso be prepared by the radical copolymerization in solution oremulsion.

The graft copolymer according to the invention comprises the stockcopolymer (A) described above and a polyamide oligomer having a primaryamino group at one end of its molecule (B) grafted on the stockcopolymer (A). That is, side chains derived from the polyamide oligomer(B) are bonded to the stock copolymer (A).

The polyamide oligomer (B) used herein has a primary amino group at oneend of the molecule and a carboxyl group at the other end of themolecule, which has usually been inactivated byencapsulating(endcapping) with a primary amine. The encapsulation of thecarboxyl group of the polyamide oligomer with a primary amine may becarried out by a method known per se. The graft copolymerization of thestock copolymer (A) with the polyamide oligomer (B) proceeds by thereaction of the primary amino group at one end of the molecule of thepolyamide oligomer (B) and a carbonyl group contained in the stockcopolymer (A).

The reaction of the carbonyl group in the stock copolymer (A) and theterminal primary amino group in the polyamide oligomer is presumed to beformation of a pyrrole ring or Schiff's base, as illustrated by thefollowing schemes. ##STR1##

The formation of the graft copolymer according to the invention can beconfirmed, for example, by thin layer chromatography. For example, whena graft copolymer is spotted on a thin layer of silica gel and thendeveloped with 1:1 toluene-2,2,2-trifluoroethanol mixture, it exhibits aR_(f) value distinct from those of the starting materials. In fact,while the polyamide oligomer and stock copolymer normally exhibit R_(f)values of 0 and from 0.3 to 0.8, respectively, the R_(f) value of thegraft copolymer is normally on the order of from 0.1 to 0.2.

The polyamide oligomer (B) should preferably have a number averagemolecular weight of from 600 to 10,000, preferably from 600 to 4,000.With polyamide oligomers having a number average molecular weight ofless than 600, an appreciable improvement to heat resistance of theresulting copolymer will not be attained. A number average molecularweight substantially in excess of 10,000 retards the graft reaction,making it difficult to enhance the graft efficiency.

As the polyamide oligomer (B), there can be used herein homopolymers andcopolymers of various lactams having from 4 to 12 carbon atoms,ω-aminocarboxylic acids having from 3 to 16 carbon atoms and nylon saltsof aliphatic alicyclic or aromatic dicarboxylic acid and aliphaticalicyclic or aromatic diamine having from 3 to 16 carbon atoms. One ofterminal of the polyamide oligomer is encapsulated with a primary aminehaving from 1 to 20 carbon atoms.

Examples of such polyamide oligomer (B) include, for example,homopolymers and copolymers of caprolactam, laurolactam andhexamethylene diammonium adipate, such as oligomers of nylon 6, nylon66, nylon 11, nylon 12, nylon 6/66, nylon 6/12 and nylon 46, with oneterminal of the molecule end-capped(encapsulated) with n-butyl amine,n-hexyl amine n-octyl amine or other primary amine.

The melting point of the polyamide oligomer (B) is preferably from 130°to 230° C. The melting point of the polyamide oligomer may be adjustedby selecting the kind of monomer used in cases of homopolymers and thekind and proportion of the monomers used in cases of copolymers.

If a polyamide oligomer which is not end-capped with a primary amine atone end of the molecule is grafted onto the stock copolymer (A), themolecular weight of the oligomer is increased during the grafting, andthus, it becomes difficult to efficiently prepare the desired graftcopolymer. On the other hand, if a polyamide oligomer having primaryamino groups at both the terminals of the molecule is grafted onto thestock copolymer (A), cross-linking takes place along, and thus, itbecomes difficult to prepare a graft copolymer having goodprocessability.

The graft copolymer according to the invention preferably comprises from60 to 99 parts, in particular from 70 to 98 parts, by weight of thestock copolymer (A) and from I to 40 parts, in particular from 2 to 30parts, by weight of the polyamide oligomer (B) grafted on the stockcopolymer (A), although the proportion may vary depending upon theintended use of the graft copolymer. With unduly small amount of thegrafted polyamide oligomer (B), an appreciable improvement to heatresistance will not be achieved. Whereas if the amount of the graftedpolyamide oligomer (B) exceeds the upper limit mentioned above, theresulting graft copolymer will have insufficient adhesive properties foruse in adhesion of non-rigid vinyl chloride resins, although it may havean improved heat resistance.

The graft copolymer according to the invention can be prepared bybringing the stock copolymer (A) in intimate contact with the polyamideoligomer (B) in the presence or absence of a solvent. The reactiontemperature may normally be within the range between 50° and 250° C. Ifa solvent is used, such solvents capable of dissolving both the startingmaterials as fluorine-containing alcohols, for example,1,1,1,3,3,3-hexafluoroisopropanol and 2,2,2-trifluoroethanol arepreferred. When no solvent is used, both the starting materials may bebrought in intimate contact to each other by sufficiently kneading themtogether at a temperature above their melting points.

While the graft polymerization of the polyamide oligomer (B) onto thestock copolymer (A) does not require any catalyst, it can be acceleratedby the presence of an acid. Suitable acids include, for example,sulfuric acid, hydrochloric acid, phosphoric acid and other inorganicacids as well as p-toluenesulfonic acid, chloroacetic acid,trifluoroacetic acid and other organic acids.

It has been found advantageous to prepare the graft copolymer accordingto the invention by reacting the stock coplymer (A) and the polyamideoligomer (B) in the presence of a carboxyl group containing compoundhaving a number average molecular weight of from 200 to 10,000,preferably from 250 to 5,000 and an acid value of from 15 to 300,preferably from 30 to 200 . If the number average molecular weight ofthe carboxyl group containing compound used is unduly low, the resultingcopolymer tends to contain an undesirably high content of volaties.Whereas carboxyl group containing compounds having a number averagemolecular weight of substantially in excess of the above-mentioned upperlimit tend to be incompatible with the starting materials, leading toreduction in effect of accelerating the reaction. Likewise, smaller acidnumbers than prescribed above tend to lead to reduction in the catalyticactivity of the carboxyl group containing compound. On the other hand,unduly large acid numbers tend to invite incompatibility of the carboxylgroup containing compound with the starting materials.

Suitable carboxyl group containing compounds include, for example, waxessuch as montanic acid, montan wax and polyethylene wax grafted withacrylic acid; carboxyl group containing tackifying resins such as rosin,hydrogenated rosin, partially esterified rosin and hydrocarbon resinsgrafted with acrylic acid; carboxyl group containing liquid rubbers suchas carboxylated polyisoprene and carboxylated polybutadiene; andcarboxyl group containing low molecular weight polymers of olefin suchas low molecular weight copolymers of ethylene with acrylic ormethacrylic acid.

While the amount of the carboxyl group containing compound used is notvery critical, use of the carboxyl group containing compound in anamount of at least 0.5 part, preferably at least 1 part, more preferablyat least 2 parts by weight, based on 100 parts by weight of the combinedweight of the stock copolymer (A) and the polyamide oligomer (B), isdesirable. In the reaction of the stock copolymer (A) with the polyamideoligomer (B) under molten conditions, as the amount of the carboxylgroup containing compound is increased, the viscosity of the reactionsystem is lowered. The resulting graft copolymer is incorporated withthe carboxyl group containing compound employed. In cases wherein thegraft copolymer should not be incorporated with a lot of the carboxylgroup containing compound because of the intended use of the graftcopolymer, use of the carboxyl group containing compound in an amount ofnot more than 100 parts, preferably not more than 20 parts, morepreferably not more than 10 parts by weight, based on 100 parts byweight of the combined weight of the stock copolymer (A) and thepolyamide oligomer (B), is desirable. However, in cases wherein thegraft copolymer is to be used in such a field where it may contain a lotof the carboxyl group containing compound, the graft reaction may becarried out in the presence of more than 100 parts by weight, based on100 parts by weight of the combined weight of the stock copolymer (A)and the polyamide oligomer (B), of the carboxyl group containingcompound.

The use of the carboxyl group containing compound in the reaction of thestock copolymer (A) and the polyamide oligomer (B) is advantageous inthat products having better heat resistance and transparency are easilyobtained.

The invention further provides a composition for use as a startingmaterial in the preparation of a graft copolymer which comprises a stockcopolymer (A) of at least one monomer selected from esters ofunsaturated carboxylic acids and vinyl esters (a), ethylene (b) andcarbon monoxide (c), and a polyamide oligomer having a primary aminogroup at one end of its molecule (B),

Such a composition according to the invention can be obtained simply bydry blending the stock copolymer (A) with the polyamide oligomer (B), orby intimately admixing both the (A) and (B) under such conditions thatthey do not substantially react to each other. The composition may bemelt extruded, while effecting the desired reaction, into a desiredshaped article or onto an adherend to form a desired coating.

The structure of the graft copolymer according to the invention can beconfirmed by its ¹³ C nuclear magnetic resonance absorption spectrum (¹³C-NMR), infrared absorption spectrum (IR) and temperature-melt viscositycurve.

The graft copolymer according to the invention is excellent in heatresistance in that it has a heat distortion temperature higher than thatof the starting stock copolymer, and in many cases, the tensile strengthat break of the graft copolymer is comparable to or higher than that ofthe stock copolymer. The graft copolymer according to the inventionexhibits good adhesion to non-rigid vinyl chloride resis and othermaterials, and the adhesion is excellently heat resistant. Furthermore,when laminated with a non-rigid vinyl chloride resin, the graftcopolymer is less liable to accept a plasticizer contained in thenon-rigid resin, than the stock copolymer is under the same conditions,indicating that an advantage of the graft copolymer according to theinvention is that the troubles of getting rigid and surface texturedeterioration of the resin may be reduced.

The graft copolymer according to the invention, as such or blended withvarious additives or other materials, can be used as an adhesive or aheat-sealer for various materials. Adherend materials for which thegraft copolymer according to the invention may be suitably used as anadhesive, include, for example, polyvinyl chloride, polyvinylidenechloride, polyester resins, polyamide resins, metals, wood andpolyolefin foams. The graft copolymer adhesive may be applied to anadherend by various method, for example, by extrusion coating the graftcopolymer onto the adherend, hot pressing a preformed film of the graftcopolymer on the adherend, roll coating the graft copolymer onto theadherend by means of a roll coater. When the graft copolymer accordingto the invention is used as a hot melt adhesive, it may be incorporatedwith a tackifying resin, a plasticizer and a wax.

The graft copolymer according to the invention may also be used as amodifier resin for various polymers such as polyvinyl chloride,polyamide resins, polyester resins and polycarbonates.

If desired, the graft copolymer according to the invention may beincorporated with various additves such as weathering agents,antioxidants, pigments, dyes, antistatic agents and various fillers.

EFFECT OF THE INVENTION

The novel graft copolymer according to the invention has a high heatdistortion temperature and exhibits excellent heat resistance andadhesion properties. It is useful as an adhesive, in particular fornon-rigid vinyl chloride resin. When it is used as an adhesive for anon-rigid vinyl chloride resin, a plasticizer contained in the resin isnot liable to transfer from the resin to the graft copolymer.

The graft polymer which is excellent in not only heat resistance butalso transparency can be easily prepared by effecting the reactionbetween the stock copolymer (A) and the polyamide oligomer (B) in thepresence of a carboxyl group containing compound having a number averagemolecular weight of from 200 to 10,000 and an acid value of from 15 to300.

The invention will now be illustrated by the following examples in whichparts, percentages and proportions are all by weight, unless otherwisespecified.

Methods and conditions for measurement and testing used herein are asfollows.

STOCK COPOLYMER

Composition of a stock copolymer was determined by a ¹³ C-NMR. Chemicalshifts of carbon atoms of ##STR2## derived from vinyl acetate, that of##STR3## derived from n-butyl acrylate and that of >C═O derived fromcarbon monoxide are 172 ppm, 175 ppm and 214 ppm, respectively.

Melt flow rate was measured at a temperature of 190° C. under a load of2,160 g.

Weight average molecular weight in terms of polystyrene (PS) wasdetermined by subjecting a stock copolymer solution in o-dichlorobenzeneat a temperature of 135° C., using polystyrene as a standard.

POLYAMIDE OLIGOMER

Viscosity in sulfuric acid was measured on a solution of a polyamideoligomer in 98% sulfuric acid, by means of an Ostwald viscometer, inaccordance with JIS K 6810.

Number average molecular weight was determined by calculating a numberaverage polymerization degree from the viscosity in sulfuric acidmeasured as described above in accordance with the following equationand then calculate a number average molecular weight based on thepolymerization degree.

Polymerization degree=(Viscosity-1.05)×100. In the case of acopolyamide, the calculation was carried out, assuming the recurringunits were 6 nylon.

Melting point was measured by means of a DSC supplied by Du Pont, usinga rate of temperature rise of 10° C./10 min.

Content of terminal amino group was determined by titration.

Structure of main chain is indicated in Tables below by marks "6","6/66", "6/12", and "12/66" designating a polymer of ε-caprolactam, acopolymer of ε-caprolactam and heximethylene diammonium diadipate, acopolymer of ε-caprolactam and ω-laurolactam, and ω-laurolactam andhexamethylene diammonium diadipate, respectively.

GRAFT COPOLYMER

Test sheets for the evaluation of graft copolymers were prepared bycompression molding at a temperature of 180° C. or 230° C.

Melt flow rate was measured at a temperature of 190° C. under a load of2,160 g and at a temperature of 230° C. under a load of 2,160 g.

Tensile strength at break and elongation at break were determined on aNo. 4 dummbell test specimen prescribed in JIS K 6301, using a crossheadspeed of 200 mm/min.

Endothermic peaks were measured by means of a DSC supplied by Du Pont,using a rate of temperature rise of 10° C./10 min.

Adhesion to non-rigid PVC was measured as follows. A graft copolymer washot pressed to a sheet having a thickness of 0.2 mm. The sheet wassandwiched between-two sheets of a non-rigid PVC (PVC/DOP =100/60, 0.2mm in thickness), and the assembly was heat sealed at a temperature of120° C., under a pressure of 1 kg/cm² for 5 seconds to prepare a testspecimen. The specimen so prepared was conditioned at a temperature of23° C. for 1 day and measured for initial adhesion. Also the specimen soprepared was maintained at a temperature of 50° C. for a period of 3months, conditioned at a temperature of 23° C. for 1 day and measuredfor adhesion. The adhesion (in kg/25 mm) was measured by T-peel testusing an autograph supplied by SHIMAZU Seisakusho at a crosshead speedof 300 mm/min.

Shear adhesive failure temperature was measured as follows. A graftcopolymer was hot pressed to a sheet having a thickness of 0.2 mm. Thesheet was sandwiched between two sheets of kraft paper, and the assemblywas heat sealed at a temperature of 120° C., under a pressure of 1kg/cm² for 5 seconds to prepare a test specimen. Using the test specimenso prepared, bond failure temperature was determined in accordance withJIS K 6844 under a load of 1 kg and at a rate of temperature rise of 24°C./hr.

DOP swelling (Weight gain after immersion in DOP) was measured asfollows. A test piece of 30 mm×10 mm was punched out from a 1 mm thicksheet of a graft copolymer, immersed in dioctyl phthalate (DOP) for aperiod of 14 days at a temperature of 23° C., and at the end of theperiod a weight gain in % of the test specimen, which is referred toherein as DOP swelling, was determined.

¹³ C nuclear magnetic resonance absorption spectrum was measured on asolution of 600 mg of a copolymer in 3 cc oftoluene/2,2,2-trifluoroethanol (1/1).

Device used: JNM-GX270 (67.8 MHz), supplied by NIPPON DENSHI K.K. (JEOL)

Temp. of measurement: 63.0° C.

Number of integrations: 30,000

Fourier transfer infrared absorption spectrum was measured on a pressedsheet of a graft copolymer having a thickness of 0.1 mm in Examples 9and 10.

Device used: FTS-40, supplied by BIO RAD K. K.

Resolution: 4.0 cm⁻¹

Number of integrations: 64

Melt viscosity was measured using an Instron capillary rheometer, attemperatures of 170°, 190°, 210° and 230° C., and at shear rates of15.8, 52.7, 158, 527, 1580 and 5266 sec⁻¹, respectively.

Transparency was visually evaluated on a pressed sheet prepared bycompression molding at a temperature of 230° C.

Load drop temperature was determined on the same test specimen as usedin testing tensile strength at break, under a load of 2 kg/cm² and at arate of temperature rise of 24° C./hr.

Infrared absorption spectrum was measured on a pressed sheet having athickness of 50 μm prepared at a temperature of 230° C. in Example 21,and that of hydrogenated rosin was measured by melt coating thehydrogenated rosin onto a KBr plate.

In the following examples, the graft polymerzation was carried out asfollows, unless otherwise specified. A 50 ml laboplast mill supplied byTOYO SEIKI K. K. was heated to the indicated temperature, and chargedwith the stock copolymer and the polyamide oligomer in an amount of 50 gin total, and with the indicated carboxyl group containing compound inthe indicated proportion, and the resulting admixture was melt mixedunder conditions including 50 rpm of a rotor and a period of 10 minutes.At the end of the period, the reaction mixture was taken out.

EXAMPLE 1

A Labophast mill was charged with 95 parts of an ethylene-vinylacetate-carbon monoxide terpolymer (63% of ethylene, 28% of vinylacetate and 9% of carbon monoxide; melt flow rate of 35 g/10 min. at190° C.; weight average molecular weight of 141,000 in terms ofpolystyrene) and 5 parts of nylon 6 oligomer endcapped with n-butylamine (number average molecular weight of 1,960; NH₂ content of 5.1×10⁻⁴mole/g; melting point of 213° C.), 50 g in total, and the mixture wasmelt mixed for 10 minutes under conditions of 230° C. and 50 ppm. Theresulting graft copolymer was tested. The results are shown in Table 1.

EXAMPLES 2 TO 5

Example 1 was repeated except that the indicated proportion of theindicated polyamide oligomer and the indicated reaction temperature wereused. The results are shown in Table 1.

The stock copolymer and polyamide oligomer used in Example 4 as well asthe resulting graft copolymer were subjected to thin layerchromatography. A solution of each compound intoluene/2,2,2-trifluoroethanol(1/1) was spotted on a thin layer ofsilica gel and developed with toluene/2,2,2-trifluoroethanol(1/1)solution. The graft copolymer exhibited Rf value of 0.1. Whereas thestock copolymer exhibited Rf value widely distributing from 0.3 to 0.7.The Rf balue of the polyamide oligomer was 0.

FIG. 1 shows a ¹³ C-NMR chart of the graft copolymer of Example 4.

COMPARATIVE EXAMPLE 1

Performances of the starting stock copolymer used in Examples 1 to 5 areshown in Table 1.

EXAMPLE 6

A dry blend of 90 parts of pellets of the terpolymer used in Example 1and 10 parts of powder of the polyamide oligomer used in Example 1 wasextruded through a 30 mm single screw extruder (L/D=32, Dullmage screw)under conditions of 40 rpm of screw and 230° C. to prepare a graftcopolymer. The results are shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________                        Example 1                                                                           Example 2                                                                           Example 3                                                                           Example 4                                                                           Example 5                                                                           Comp. Ex.                                                                            Example              __________________________________________________________________________                                                             6                    Stock copolymer                                                               Composition                                                                   Vinyl acetate                                                                              (wt %) 28    28    28    28    28    28     28                   Ethylene     (wt %) 63    63    63    63    63    63     63                   Carbon monoxide                                                                            (wt %) 9     9     9     9     9     9      9                    Melt flow rate                                                                             (g/10 min.)                                                                          35    35    35    35    35    35     35                   Wt. av. molecular weight                                                                          1.41 × 10.sup.5                                                               1.41 × 10.sup.5                                                               1.41 × 10.sup.5                                                               1.41 × 10.sup.5                                                               1.41 × 10.sup.5                                                               1.41 × 10.sup.5                                                                1.41 ×                                                                  10.sup.5             in terms of PS                                                                Polyamide oligomer                                                            Structure of main chain                                                                           6     6/66  6/66  6/12  12/66 --     6                    Viscosity in H.sub.2 SO.sub.4                                                                     1.22  1.30  1.37  1.40  1.40  --     1.22                 M.p.         (°C.)                                                                         213   190   173   147   145   --     213                  Number av. molecular                                                                              1960  2830  3620  3960  3960  --     1960                 weight                                                                        Content of --NH.sub.2                                                                      (mole/g)                                                                             5.1   3.3   2.8   2.4   2.2   --     5.1                  group × 10.sup.4                                                        Proportion of stock                                                                        (wt %) 95    90    90    90    90    100    90                   copolymer                                                                     Proportion of polyamide                                                                    (wt %) 5     10    10    10    10    0      10                   oligomer                                                                      Reaction temp.                                                                             (°C.)                                                                         230   200   200   160   160   --     230                  Graft copolymer                                                               Melt flow rate at 190° C.                                                           (g/10 min.)                                                                          0.05  0.9   1.3   4.3   0.8   35     16.0                 Tensile strength at break                                                                  (MPa)  6.3   4.4   5.2   5.3   3.9   3.6    4.2                  Elongation at break                                                                        (%)    770   720   700   820   730   1030   930                  Endothermic peaks by                                                                       (°C.)                                                                         54,212                                                                              177   56,162                                                                              53,130                                                                              53,137                                                                              45     --                   DSC                                                                           Performances                                                                  Initial adhesion to non-                                                                   (kg/25 mm)                                                                           4.5   4.1   4.3   4.6   3.9   5.4    --                   rigid vinyl chloride resin                                                    Adhesion to non-rigid                                                                      (kg/25 mm)                                                                           4.7   --    --    --    --    4.3    --                   vinyl chloride resin after                                                    3 months at 50° C.                                                     Shear adhesive failure                                                                     (°C.)                                                                         130   74    73    72    72    63     138                  temperature                                                                   Wt gain after 14 days                                                                      (%)    180   170   165   180   180   285    140                  immersion in DOP at                                                           23° C.                                                                 __________________________________________________________________________

EXAMPLES 7 TO 14 AND COMPARATIVE EXAMPLE 2

Example 1 was repeated except that an ethylene-n-butyl acrylate-carbonmonoxide terpolymer (60% of ethylene, 30% of n-butyl acrylate and 10% ofcarbon monoxide; melt flow rate of 6 g/10 min. at 190° C.; weightaverage molecular weight of 420,000 in terms of polystyrene) and thepolyamide oligomer indicated in Table 2 in proportions indicated in thesame table were reacted. The results are shown in Table 2.

For a comparative purpose, performances of the starting stock copolymerare also shown in the same table as Comparative Example 2.

Infrared absorption spectra of the graft copolymers of Examples 9 and 10are shown in FIGS. 2 and 3, respectively.

Melt-behavior (temperature-melt viscosity curves) of the graft copolymerof Example 9 is shown in FIG. 4. It is revealed from FIG. 4 that whilethe melt viscosity decreases as the temperature rises, the viscositydecrease is considerably prominent near the melting point (higherendothermic peak) and fairly moderate above the melting point Such amelt behavior is inherent in graft copolymers.

                                      TABLE 2                                     __________________________________________________________________________                               Example 7                                                                           Example 8                                                                           Example 9                                                                           Example 10                                                                          Example                    __________________________________________________________________________                                                       11                         Stock copolymer                                                               Composition                                                                   n-Butyl acrylate    (wt %) 30    30    30    30    30                         Ethylene            (wt %) 60    60    60    60    60                         Carbon monoxide     (wt %) 10    10    10    10    10                         Melt flow rate      (g/10 min.)                                                                          6     6     6     6     6                          Wt. av. molecular weight in terms of PS                                                                  4.2 × 10.sup.5                                                                4.2 × 10.sup.5                                                                4.2 × 10.sup.5                                                                4.2 × 10.sup.5                                                                4.2 × 10.sup.5       Polyamide oligomer                                                            Structure of main chain    6     6     6     6     6/66                       Viscosity in H.sub.2 SO.sub.4                                                                            1.22  1.22  1.22  1.22  1.30                       M.p.                (°C.)                                                                         213   213   213   213   190                        Number av. molecular weight                                                                              1960  1960  1960  1960  2830                       Content of --NH.sub.2 group × 10.sup.4                                                      (mole/g)                                                                             5.1   5.1   5.1   5.1   3.3                        Proportion of stock copolymer                                                                     (wt %) 98    95    90    80    90                         Proportion of polyamide oligomer                                                                  (wt %) 2     5     10    20    10                         Reaction temp.      (°C.)                                                                         230   230   230   230   230                        Graft copolymer                                                               Melt flow rate at 190° C.                                                                  (g/10 min.)                                                                          6.5   1.1   0.6   0.05  0.06                       230° C.      (g/10 min.)                                                                          --    8.6   7.1   --    0.29                       Tensile strength at break                                                                         (MPa)  --    3.5   3.4   --    3.1                        Elongation at break (%)    --    1000  990   --    530                        Endothermic peaks by DSC                                                                          (°C.)                                                                         --    --    52,213                                                                              --    --                         Performances                                                                  Initial adhesion    (kg/25 mm)                                                                           4.6   4.6   5.0   4.1   3.9                        to non-rigid vinyl chloride resin                                             Adhesion to non-rigid vinyl chloride                                                              (kg/25 mm)                                                                           5.0   4.6   3.3   3.2   --                         resin after 3 months at 50° C.                                         Shear adhesive failure temperature                                                                (°C.)                                                                         69    84    100   138   73                         Wt gain after 14 days immersion                                                                   (%)    419   370   295   205   241                        in DOP at 23° C.                                                       __________________________________________________________________________                               Example 12                                                                            Example 13                                                                           Example 14                                                                           Comp. Ex.                    __________________________________________________________________________                                                     2                            Stock copolymer                                                               Composition                                                                   n-Butyl acrylate    (wt %) 30      30     30     30                           Ethylene            (wt %) 60      60     60     60                           Carbon monoxide     (wt %) 10      10     10     10                           Melt flow rate      (g/10 min.)                                                                          6       6      6      6                            Wt. av. molecular weight in terms of PS                                                                  4.2 × 10.sup.5                                                                  4.2 × 10.sup.5                                                                 4.2 ×  10.sup.5                                                                4.2 × 10.sup.5         Polyamide oligomer                                                            Structure of main chain    6/66    6/12   12/66  --                           Viscosity in H.sub.2 SO.sub.4                                                                            1.37    1.40   1.40   --                           M.p.                (°C.)                                                                         173     147    145    --                           Number av. molecular weight                                                                              3620    3960   3960   --                           Content of --NH.sub.2 group × 10.sup.4                                                      (mole/g)                                                                             2.8     2.4    2.2    --                           Proportion of stock copolymer                                                                     (wt %) 90      90     90     100                          Proportion of polyamide oligomer                                                                  (wt %) 10      10     10     0                            Reaction temp.      (°C.)                                                                         230     230    230    --                           Graft copolymer                                                               Melt flow rate at 190° C.                                                                  (g/10 min.)                                                                          0.03    0.7    0.03   6.0                          230° C.      (g/10 min.)                                                                          0.17    2.9    0.09   15.0                         Tensile strength at break                                                                         (MPa)  2.8     3.0    2.8    2.9                          Elongation at break (%)    510     610    480    920                          Endothermic peaks by DSC                                                                          (°C.)                                                                         --      --     --     52                           Performances                                                                  Initial adhesion    (kg/25 mm)                                                                           3.8     3.6    3.5    4.8                          to non-rigid vinyl chloride resin                                             Adhesion to non-rigid vinyl chloride                                                              (kg/25 mm)                                                                           --      --     --     3.1                          resin after 3 months at 50° C.                                         Shear adhesive failure temperature                                                                (°C.)                                                                         75      91     85     66                           Wt gain after 14 days immersion                                                                   (%)    248     280    254    460                          in DOP at 23° C.                                                       __________________________________________________________________________

EXAMPLES 15 TO 18

Example 9 was repeated except that the stock copolymer indicated inTable 3was used.

The results are shown in Table 3.

                                      TABLE 3                                     __________________________________________________________________________                               Example 15                                                                          Example 16                                                                          Example 17                                                                          Example 18                       __________________________________________________________________________    Stock copolymer                                                               Composition                                                                   n-Butyl acrylate    (wt %) 25    25    25    9                                Ethylene            (wt %) 66    71    71    69                               Carbon monoxide     (wt %) 9     4     4     12                               Melt flow rate      (g/10 min.)                                                                          25    90    20    150                              Wt. av. molecular weight in terms of PS                                                                  26.3 × 10.sup.4                                                               14.4 × 10.sup.4                                                               23.3 × 10.sup.4                                                               20.0 × 10.sup.4            Polyamide oligomer                                                            Structure of main chain    6     6     6     6                                Viscosity in H.sub.2 SO.sub.4                                                                            1.22  1.22  1.22  1.22                             M.p.                (°C.)                                                                         213   213   213   213                              Number av. molecular weight                                                                              1960  1960  1960  1960                             Content of --NH.sub.2 group × 10.sup.4                                                      (mole/g)                                                                             5.1   5.1   5.1   5.1                              Proportion of stock copolymer                                                                     (wt %) 90    90    90    90                               Proportion of polyamide oligomer                                                                  (wt %) 10    10    10    10                               Reaction temp.      (°C.)                                                                         230   230   230   230                              Graft copolymer                                                               Melt flow rate at 190° C.                                                                  (g/10 min.)                                                                          0.27  13.1  0.77  55.0                             230° C.             3.7   35.9  3.8   150                              Tensile strength at break                                                                         (MPa)  4.61  2.29  4.31  2.82                             Elongation at break (%)    740   675   730   590                              Performances                                                                  Shear adhesive failure temperature                                                                (°C.)                                                                         87    73    80    76                               Wt gain after 14 days immersion                                                                   (%)    154   128   91    97                               in DOP at 23° C.                                                       __________________________________________________________________________

EXAMPLE 19

A Labophast mill was charged with 90 parts of an ethylene-n-butylacrylate-carbon monoxide terpolymer (60% of ethylene, 30% of n-butylacrylate and 10% of carbon monoxide; melt flow rate of 6 g/10 min. at190° C.; weight average molecular weight of 420,000 in terms ofpolystyrene), 10 parts of nylon 6 oligomer end-capped with n-butyl amine(number average molecular weight of 1,960; NH₂ content of 5.1×10⁻⁴mole/g; melting point of 213° C.), the combined weight of the terpolymerand the polyamide oligomer being 50 g, and 3 parts of hydrogenated rosin("KR 610", supplied by ARAKAWA Kagaku K. K. and having an acid value of170 and a number average molecular weight of 300), and the mixture wasmelt mixed for 10 minuts under conditions of 230° C. and 50 ppm. Theresulting graft copolymer was tested.

The results are shown in Table 4.

EXAMPLE 20

Example 19 was repeated except that 5 parts of the hydrogenated rosinwas additionally used.

The results are shown in Table 4.

EXAMPLE 21

Example 19 was repeated except that 7 parts of the hydrogenated rosinwas additionally used.

The results are shown in Table 4.

One gram of the graft copolymer so prepared was extracted with 200 ml ofacetone at room temperature. Infrared absorption spectra of the graftcopolymers before and after the extraction are shown in FIGS. 5 and 6,respectively. The absorption based on the hydrogenated rosin appearingin the chart shown in FIG. 5 disappears in the chart shown in FIG. 6,indicating that the hydrogenated rosin is not taken up the reactionsystem and it would act as a catalyst. FIG. 7 shows an IR absorptionspectrum of the hydrogenated rosin used.

EXAMPLES 22 AND 23

Example 19 was repeated except that the hydrogenated rosin was replacedwith the indicated proportion of a low molecular weight ethylene-acrylicacid copolymer ("AC 580" supplied by Allied Chemical Company and havingan acid value of 75 and a number average molecular weight of 3,200),which is abbreviated as EAA in Table 4.

The results are shown in Table 4.

REFERENCE EXAMPLE 1

Example 19 was repeated except that the hydrogenated rosin was replacedwith the indicated proportion of a glycerol ester of a hydrogenatedrosin ("KE 811" supplied by ARAKAWA Kagaku K. K., and having an acidvalue of 10 and a number average molecular weight of 900).

The results are shown in Table 4.

REFERENCE EXAMPLE 2

Example 19 was repeated except that the hydrogenated rosin was replacedwith the indicated proportion of a terpene phenolic resin ("IYS polystarT100", supplied by YASUHARA Yushi K. K., and having an acid value ofless than 1 and a number average molecular weight of 550).

The results are shown in Table 4.

REFERENCE EXAMPLE 3

Example 19 was repeated except that the hydrogenated rosin was replacedwith the indicated proportion of a styrenic hydrocarbon resin ("FTR6100", supplied by MITSI Petrochemical Industries Ltd., and having anacid value of less than 0.1 and a number average molecular weight of750).

The results are shown in Table 4.

EXAMPLE 24

Example 20 was repeated except that the polyamide oligomer was replacedwith that indicated in Table 4.

The results are shown in Table 4.

REFERENCE EXAMPLE 4

Example 19 was repeated except that the hydrogenated rosin was not used.

The results are shown in Table 4.

                                      TABLE 4                                     __________________________________________________________________________                               Example 19                                                                            Example 20                                                                            Example 21                                                                            Example                                                                             Example              __________________________________________________________________________                                                             23                   Stock copolymer                                                               Composition                                                                   n-Butyl acrylate    (wt %) 30      30      30      30    30                   Ethylene            (wt %) 60      60      60      60    60                   Carbon monoxide     (wt %) 10      10      10      10    10                   Melt flow rate      (g/10 min.)                                                                          6       6       6       6     6                    Wt. av. molecular weight in terms of PS                                                                  4.2 × 10.sup.5                                                                  4.2 × 10.sup.5                                                                  4.2 × 10.sup.5                                                                  4.2 × 10.sup.5                                                                4.2 ×                                                                   10.sup.5             Polyamide oligomer                                                            Structure of main chain    6       6       6       6     6                    Viscosity in H.sub.2 SO.sub.4                                                                            1.22    1.22    1.22    1.22  1.22                 M.p.                (°C.)                                                                         213     213     213     213   213                  Number av. molecular weight                                                                              1960    1960    1960    1960  1960                 Content of --NH.sub.2 group × 10.sup.4                                                      (mole/g)                                                                             5.1     5.1     5.1     5.1   5.1                  Additive                                                                      Kind (general name)        Hydrogenated                                                                          Hydrogenated                                                                          Hydrogenated                                                                          EAA   EAA                                             rosin   rosin   rosin                              Acid value          (KOH mg/g)                                                                           170     170     170     75    75                   Number av. molecular weight                                                                              300     300     300     3200  3200                 Proportion of stock copolymer                                                                     (wt %) 90      90      90      90    90                   Proportion of polyamide oligomer                                                                  (wt %) 10      10      10      10    10                   Proportion of additive                                                                            (wt %) 3       5       7       5     10                   Reaction temp.      (°C.)                                                                         230     230     230     230   230                  Graft copolymer                                                               Melt flow rate at 190° C.                                                                  (g/10 min.)                                                                          0.02    0.01    0.01    0.05  0.01                 230° C.      (g/10 min.)                                                                          2.3     2.5     2.7     2.5   2.5                  Tensile strength at break                                                                         (MPa)  4.99    4.53    4.79    5.17  --                   Elongation at break (%)    550     530     470     670   --                   Performances                                                                  Transparency               Transparent                                                                           Transparent                                                                           Transparent                                                                           Translucent                                                                         Translucent          Load drop temp.     (°C.)                                                                         86      89      85      76    110                  Shear adhesive failure temperature                                                                (°C.)                                                                         --      204     --      199   190                  Wt gain after 14 days immersion                                                                   (%)    --      131     --      158   137                  in DOP at 23° C.                                                       __________________________________________________________________________                               Ref. Ex. 1                                                                            Ref. Ex. 2                                                                          Ref. Ex. 3                                                                            Example                                                                               Ref. Ex.             __________________________________________________________________________                                                             4                    Stock copolymer                                                               Composition                                                                   n-Butyl acrylate    (wt %) 30      30    30      30      30                   Ethylene            (wt %) 60      60    60      60      60                   Carbon monoxide     (wt %) 10      10    10      10      10                   Melt flow rate      (g/10 min.)                                                                          6       6     6       6       6                    Wt. av. molecular weight in terms of PS                                                                  4.2 × 10.sup.5                                                                  4.2 × 10.sup.5                                                                4.2 × 10.sup.5                                                                  4.2 × 10.sup.5                                                                  4.2 ×                                                                   10.sup.5             Polyamide oligomer                                                            Structure of main chain    6       6     6       6/12    6                    Viscosity in H.sub.2 SO.sub.4                                                                            1.22    1.22  1.22    1.40    1.22                 M.p.                (°C.)                                                                         213     213   213     147     213                  Number av. molecular weight                                                                              1960    1960  1960    3960    1960                 Content of --NH.sub.2 group × 10.sup.4                                                      (mole/g)                                                                             5.1     5.1   5.1     2.4     5.1                  Additive                                                                      Kind (general name)        Glycerol                                                                              Terpene                                                                             Styrenic                                                                              Hydrogenated                                            ester of                                                                              phenol                                                                              hydrocarbon                                                                           rogin                                                   hydrogenated                                                                  rosin                                              Acid value          (KOH mg/g)                                                                           10      <1    <0.1    170     --                   Number av. molecular weight                                                                              900     550   750     300     --                   Proportion of stock copolymer                                                                     (wt %) 90      90    90      90      90                   Proportion of polyamide oligomer                                                                  (wt %) 10      10    10      10      10                   Proportion of additive                                                                            (wt %) 5       5     5       5       0                    Reaction temp.      (°C.)                                                                         230     230   230     230     230                  Graft copolymer                                                               Melt flow rate at 190° C.                                                                  (g/10 min.)                                                                          1.3     4.2   4.8     2.6     0.6                  230°  C.     (g/10 min.)                                                                          14.7    21.4  21.4    --      7.1                  Tensile strength at break                                                                         (MPa)  3.51    3.72  3.12    3.36    3.4                  Elongation at break (%)    815     970   810     580     990                  Performances                                                                  Transparency               Opaque  Opaque                                                                              Opaque  Transparent                                                                           Opaque               Load drop temp.     (°C.)                                                                         60      59    57      56      54                   Shear adhesive failure temperature                                                                (°C.)                                                                         153     120   111     120     100                  Wt gain after 14 days immersion                                                                   (%)    196     226   225     192     295                  in DOP at 23° C.                                                       __________________________________________________________________________

What is claimed is:
 1. A process for the preparation of a graftcopolymer which comprises graft polymerizing:1 to 40% by weight, basedon the weight of said graft copolymer, of a polyamide oligomer (B)having a primary amino group at one end of its molecule and a carboxylgroup at another end of its molecule, said carboxyl group beingencapsulated with a primary amine having from 1 to 20 carbon atoms, saidpolyamide oligomer having a number average molecular weight of from 600to 10,000; onto a stock copolymer (A) including at least one monomerselected form esters of unsaturated carboxylic acids (a), ethylene (b)and carbon monoxide (c), said stock copolymer (A) having a weightaverage molecular weight of from 10⁴ to 10⁶, wherein said polyamideoligomer is graft polymerized onto said stock copolymer is the presenceof a carboxyl group containing compound being selected from the groupconsisting of rosin, hydrogenated rosin, a low molecular weightcopolymer of ethylene and and acrylic acid and a low molecular weightcopolymer of ethylene and methacrylic acid, said compound having anumber average molecular weight of from 200 to 10,000 and an acid valueof from 15 to
 300. 2. A composition for use as a starting material inthe preparation of a graft copolymer which comprises:a stock copolymer(A) including at least one monomer selected from esters of unsaturatedcarboxylic acids (a), ethylene (b) and carbon monoxide (c), said stockcopolymer (A) having a weight average molecular weight of from 10⁴ to10⁶ ; 1 to 40% by weight, based on the weight of said graft copolymer,of a polyamide oligomer (B) having a primary amino group at one end ofits molecule and a carboxyl group at another end of its molecule, saidcarboxyl group being encapsulated with a primary amine having from 1 to20 carbon atoms, said polyamide oligomer having a number averagemolecular weight of from 600 to 10,000, and a carboxyl group containingcompound being selected from the group consisting of rosin, hydrogenatedrosin, a low molecular weight copolymer of ethylene and acrylic acid anda low molecular weight copolymer of ethylene and methacrylic acid, saidcompound having a number average molecular weight of from 200 to 10,000and an acid value of from 15 to 300.